Calorie restriction (CR) delays age-related diseases in laboratory animals, and a small molecule that safely mimics its effects has been greatly sought after. There is evidence that resveratrol can mimic effects of CR in lower organisms and we have now concluded the first study of the aging intervention program. In mice, we found that resveratrol induces gene expression patterns in multiple tissues that are highly similar to those induced by CR. Moreover, elderly resveratrol-fed mice showed a marked reduction in signs of aging. These changes included reduced albuminuria, decreased inflammation and apoptosis in the vascular endothelium, increased aortic elasticity, greater motor coordination, reduced cataract formation, and preservation of bone mineral density. However, mice fed a standard diet did not live longer when treated with resveratrol beginning at mid-life. Thus it is possible to mimic transcriptional aspects of DR and delay functional decline with a safe, orally available small molecule. Our findings indicate that resveratrol treatment starting from mid-life has a range of beneficial effects in mice, but suggest that it may not be an effective strategy to increase the longevity of normal ad libitum-fed animals. Long-term resveratrol treatment mimicked important physiological and transcriptional aspects of CR in vivo, and allowed treated animals to live healthier, more vigorous lives. In addition to improving insulin sensitivity and increasing survival in mice fed a high calorie diet, we found evidence that resveratrol improves cardiovascular function, bone density, motor coordination, and delays cataracts, even in non-obese rodents. Since cardiovascular disease is a major cause of age-related morbidity and mortality in humans but not mice, it is possible that a CR mimetics such as resveratrol could have an even greater impact on human health than on mice. However, resveratrol does not seem to mimic all of the salutary effects of DR in that its introduction into the diet of normal one year old mice did not increase longevity.